REO Speedwagon’s Kevin Cronin says they’re thrilled to be back out on the road with their longtime friends in Styx. The two bands have shared the stage a number of times over the years; this year’s run is called United We Rock. But things weren't always this cozy. Cronin admits they were “adversaries for so many years and none of us really understood why.”

“It was just kind of that our album release schedule seemed to coincide, and it certainly kind of culminated in 1981 when we had Hi Infidelity coming out and they had Paradise Theatre coming out,” Cronin tells Ultimate Classic Rock. “Our records were No. 1 and No. 2 on the Billboard charts for about six months or something. It was crazy. Both albums couldn’t be No. 1, so one of us had to be No. 1 and one of us had to be No. 2, and it just so happened that either Hi Infidelity sold one more copy a week or whatever it was. So there was this kind of perceived competition, which was really just, as Tommy Shaw always says, more of a competition between the record labels. The bands, we were just doing our thing.”

Years later, Cronin and Shaw met up at a VH1 event and wondered why their bands had never done shows together. They did a couple of warm-up concerts to test the waters and found there was definite chemistry between them. Cronin realizes it was a lucky strike to find that classic-rock synergy. “I don’t think that’s something that can easily be taken for granted,” he says. “Because a lot of times a co-headline tour comes from booking agents getting together or managers getting together and trying to figure something out. But in our case, it really came from the bands. And that’s pretty rare in this day and age. That’s just another example of why the REO and Styx partnership works so well.”

Plus, Cronin laughs, “at this point in the game for us, if we’re going to go and spend the whole summer with people, we kind of want it to be people that we enjoy being with. And then there’s obviously other considerations too. You want it to be music that’s compatible and that will appeal to the largest number of people possible, because that’s what makes it fun. You get the REO fans mixed in with the Styx fans, and our music was all around at the same time, as far as the heyday is concerned. It works musically, it works on a personal level, and then we get the added treat of getting to hear Don Felder play the guitar every night and that is a treat.”

The two groups last toured together in 2012 for the Midwest Express tour and at that time, Cronin described their bond as being friendly but still a bit competitive. “It’s kind of like if two sports teams get together and they’re both kind of the top teams in their division, and when they meet, it’s a special game,” he explained at that time. “We love those guys, but still, we want people to leave the arena humming an REO Speedwagon song. They want people to leave the arena humming a Styx song. But at the same time, it’s a very supportive and friendly atmosphere.”

This year's tour was announced with a video that finds Shaw calling Cronin and Felder. Cronin is working out, playing basketball, hitting a punching bag and hanging upside down. Like a videoForeigner made earlier this year for their tour, the REO Speedwagon and Styx clip, which you can watch above, goes beyond the usual “Please come see us” pleas from band members.

“The day that the film crew came out to my house to shoot, it was rainy out. Originally, we were going to do it out on the deck,” Cronin recalls. “There’s a nice deck with the mountains in the background and stuff and we were going to shoot. But the weather didn’t permit it, so we had to kind of punt. I’ve got to give credit to our manager, who is also one of my closest friends in the world. He’s been with us since he was our tour manager back in 1975. So he’s been with us for a long time. We were walking around the house, looking for another place to shoot, and I went, 'You know, there’s a gym upstairs.' We went upstairs in the gym and that’s where the ideas started flowing. They dragged a bunch of equipment out to the pool house out here, and it was Tommy’s idea to set up the slam-dunk shot.”

Cronin notes that whenever the two bands get together, they’re honoring how deeply the audience has connected with their records over the years. “There's probably about 10 songs that if we don’t play them, there’s going to be an angry mob hanging out around the tour bus. So that’s really important,” he says. “And honestly, we still really love playing those songs. I still love singing those songs every night. But I think what makes for a great classic-rock experience is when you’ve got bands that are into playing the songs that got us there.”

But, as he adds, both bands are also still passionate about creating new music. Styx recently released their first new album in years, The Mission, which has been well-received by both fans and critics. They’re playing a couple of songs from the album during the new tour. REO Speedwagon also have some new music they’re sharing during their set, including one called “Whipping Boy.” "We’ve been working on [that] in soundcheck," he says. "We messed around with it a few years ago, but it wasn’t quite gelling for us. We started working on it again in the soundchecks for our warm-up shows this year, and it came together, so we’re playing that."

They're also playing a couple of songs that haven’t been performed onstage in more than 20 years. "That’s my idea of a good show -- when a band gives you the hits and also gives you a little surprise here or there that sends the message that ‘Hey, we’ve been around a long time, but our juices are still flowing.’ We’re not just sitting here regurgitating the hits. It’s about taking the hits and playing them with a new passion every year. As long as we’re still doing that, then I think we deserve to be out there.”

Cronin says he’s constantly working on new music, but the band hasn't gotten around to recording anything yet. Find Your Own Way Home, their most recent album, was released a decade ago.

“It’s really just a matter of scheduling," he explains. "We tour for about half the year, and we have kids and wives. So to come home off the road and say, ‘Okay, nice seeing you guys, we’ll be in the studio for the next six months,’ it just doesn’t work that way. If your family’s not happening, then you’re not happening. My family supports me -- I’ve got twin 17-year-old boys, and this is their junior year of high school. I just felt like this was a really important year to spend as much time at home as possible. And I’ve got to say, the Styx guys were really cool in understanding that. We were originally going to play a lot more shows, and I just wasn’t available. I just needed to be home.”

Still, he can't stay away from music for too long. “I love writing a song and then finishing the song myself so that I can play it on acoustic guitar to somebody, and then take it to the band to bring to another level," he says. "Being able to hear a great recording of a song that you made up, it’s a pretty cool feeling. It’s something that I kind of miss, because it’s been a long time since we’ve done it. I don’t think we’re done recording.”